"More than a third of investors believe prospects for success are worse than they were six months ago, and only 18 percent think they are better," said Barbara Levin, the organization's executive director.

Investors using a professional advisor tended to be more optimistic than self-directed investors, Levin said.

Twenty-three percent of investors with advisors are optimistic while only 12 percent of investors without an advisor are optimistic, according to the survey.

The survey also pointed to a periodic trend in investor worries, said Levin.

"We've done this study now for a few years, since August '98, and people seem to be more confident in April and less confident in October," she said. "October is the month of gloom. It's sort of like a period of reckoning for investors. It suggests that investors are not necessarily in control of their own emotions about the market or not necessarily always rational about the market, because October and April are short-term phenomena."